Dabigatran etexilate mesylate is a direct thrombin inhibitor, with the chemical name, β-Alanine, N-[[2-[[[4-[[[(hexyloxy)carbonyl]amino]iminomethyl]phenyl]amino]methyl]-1-methyl-1H-benzimidazole-5-yl]carbonyl]-N-2-pyridinyl-ethyl ester, methane sulfonate represented by Formula (I) below:

Dabigatran etexilate mesylate is commercially marketed as PRADAXA® by Boehringer Ingelheim Pharmaceuticals Inc. PRADAXA® is available as 75 mg capsule containing 86.48 mg dabigatran etexilate mesylate equivalent to 75 mg dabigatran etexilate and 150 mg capsule containing 172.95 mg dabigatran etexilate mesylate equivalent to 150 mg dabigatran etexilate. The recommended dose of PRADAXA® is one capsule taken twice a day with or without food. PRADAXA® is indicated to reduce the risk of stroke and systemic embolism in patients with non-valvular atrial fibrillation.
Dabigatran and its acyl glucuronides are competitive direct thrombin inhibitors. Because thrombin enables the conversion of fibrinogen into fibrin during the coagulation cascade, its inhibition prevents the development of a thrombus. Both free and clot-bound thrombin and thrombin-induced platelet aggregation are inhibited by active moieties.
WO9837075 discloses the preparation of substituted (4-benzimidazol-2yl-methylamino)-benzamidines, particularly Dabigatran etexilate. The process disclosed involves the use of column chromatography for purification thereby making the process ineffective at industrial scale. Further, 1-methyl-2-[N-[4-amidinophenyl]aminomethyl]benzimidazol-5-yl-carboxylic acid-N-(2-pyridyl)-N-(2-ethoxy carbonylethyl)amide mesylate compound is obtained in low yield.
WO2011061080 describes the preparation of Dabigatran etexilate by reacting Ethyl-3-{[(2-halomethyl-1-methyl-1H-benzimidazole-5-yl)carbonyl]-(2-pyridinyl)amino}propanoate with 4-aminobenzamidine-N-hexyl-carbamate.
CN102850326 discloses the process for preparation of Dabigatran etexilate by reacting O-mesyl derivative of Ethyl-3-{[(2-hydroxymethyl-1-methyl-1H-benzimidazole-5-yl)carbonyl]-(2-pyridinyl)amino}propanoate with 4-amino benzamidine-N-hexyl-carbamate.
WO2012153158 describes a process for preparation of Dabigatran etexilate or pharmaceutically acceptable salts thereof by using N-[4-(5-substituted-1,2,4-oxadiazol-3-yl)-phenyl]glycine. It further relates to various salts of Ethyl-N-[(2-{[4-carbamimidoylphenyl)amino]methyl}-1-methyl-1H-benzimidazole-5-yl)-carbonyl]-N-pyridine-2-yl/-β-alaninate.
There exists a need to develop a simple, cost-effective and commercially viable process for the preparation of Dabigatran etexilate or its pharmaceutically acceptable salts. The present invention provides an industrially viable process for preparation of Dabigatran etexilate or pharmaceutically acceptable salt thereof using novel compounds such as Ethyl-3-{[(2-formyl-1-methyl-1H-benzimidazole-5-yl)carbonyl]-(2-pyridinyl)amino}propanoate, Ethyl-3-{[(2-dihalomethyl-1-methyl-1H-benzimidazole-5-yl)carbonyl]-(2-pyridinyl)amino}propanoate, Ethyl-3-{[(1,2-dimethyl-1H-benzimidazole-5-yl)carbonyl]-(2-pyridinyl)amino}propanoate, or [(4-[{(hexyloxy)carbonyl]carbamimidoyl}phenyl)amino]acetic acid.